Estimated reading time: 7 minutes

When it comes to orthopedics, it is easy to get caught up in MRI and CT scans. But before jumping to advanced imaging, there is one basic investigation that should never be ignored — the X-ray.

A good X-ray can tell you a lot about a patient. It can help in diagnosis, staging, prognosis and, in many cases, guide the next step in management.

That is exactly why Conceptual Orthopedics recently brought a very useful lecture on Foot & Ankle X-Ray Interpretation by Dr. Anuj Chawla. The session takes residents through the important X-ray views, measurements, signs and common conditions that can be identified just by carefully reading the radiograph.

For orthopedic residents, especially those preparing for OSCEs, DNB exams and day-to-day clinical practice, this is an important topic to understand.

Start With the Basics: Always Look at the Patient

One of the most important points from the session is simple: do not treat the X-ray; treat the patient.

An X-ray or MRI should support your clinical assessment, not replace it.

For elective foot and ankle conditions, weight-bearing X-rays are particularly important. They show the foot and ankle under load and can reveal deformities and alignment problems that may not be obvious when the patient is lying down.

Ankle X-Ray: Know Your Three Standard Views

The three basic ankle X-ray views are:

AP view

Mortise view

Lateral view

Each view gives you different information.

In the mortise view, the medial and lateral gutters can be assessed clearly. On the lateral view, the talar domes should appear superimposed. Understanding whether you have a good-quality view is the first step before you start measuring anything.

Don’t Forget the Syndesmosis

When reading an ankle X-ray, always check the tibiofibular clear space and overlap.

The tibiofibular clear space should generally be less than 6 mm, while the overlap is also assessed on AP and mortise views. Comparing with the opposite side can be helpful when there is doubt.

Other useful measurements include:

Medial clear space

Talocrural angle

Fibular length

Dime sign

These measurements can help identify problems such as syndesmotic injury or shortening of the distal fibula.

Soft Tissue Signs Can Also Give You Clues

X-rays are not only about bones.

On the lateral ankle X-ray, the Kager’s fat pad can provide useful information. Changes in this fat pad can be seen with conditions such as retrocalcaneal bursitis.

An ankle effusion can also produce changes in the anterior and posterior soft-tissue shadows. In an appropriate clinical setting, this may raise suspicion for an occult fracture and the need for further evaluation.

Haglund’s Deformity and Achilles Problems

The X-ray can also help when assessing Achilles-related conditions.

You may see:

Haglund’s deformity

Calcification around the Achilles tendon

Retrocalcaneal spur

Two measurements discussed in the lecture are the Fowler-Phillip angle and Pavlov’s parallel pitch line. These can help assess the bony prominence associated with Haglund’s deformity.

Don’t Miss Osteochondral Lesions and Impingement

Some important foot and ankle conditions have characteristic X-ray findings.

For example, an osteochondral lesion of the talus may be visible on X-ray, especially when it is more significant.

Similarly, a posterior ankle X-ray may show an os trigonum, an accessory bone behind the talus. In symptomatic patients, this can be associated with posterior ankle impingement. In some cases, inflammation can also involve the FHL tendon.

Anterior ankle impingement may show the classic kissing osteophytes involving the distal tibia and talus.

Foot X-Rays: Weight-Bearing Matters

Moving from the ankle to the foot, the importance of weight-bearing X-rays becomes even more obvious.

They are particularly useful when assessing conditions such as:

Pes planus

Pes cavus

Other foot deformities

Alignment problems

Standing AP, oblique and lateral views allow you to assess the foot in its functional position.

A Few Angles Every Resident Should Know

Foot X-rays come with several measurements that are worth knowing, particularly for exams and clinical practice.

Some of the important ones include:

Meary’s angle

Calcaneal pitch

Lateral talocalcaneal angle

Kite’s angle

Talar uncoverage

Cyma line

These measurements help in assessing foot alignment and deformities.

For example, in pes planus, you may see a reduced calcaneal pitch, increased talocalcaneal angles and changes in Meary’s angle. Increased talar uncoverage can also indicate deformity.

Pes cavus shows the opposite pattern, with an increased calcaneal pitch and other changes in alignment.

Some X-Ray Signs Are Easy to Remember

Orthopedic residents should also be familiar with a few classic radiological signs.

These include:

Sinus tarsi see-through sign

C sign – associated with talocalcaneal coalition

Drunken waiter sign

Anteater sign – associated with calcaneonavicular coalition

These signs are especially useful for exams and OSCE discussions because a single X-ray finding can point you towards a particular diagnosis.

Don’t Forget Lisfranc Injuries

The midfoot needs careful attention, particularly when a Lisfranc injury is suspected.

Look for:

Alignment of the metatarsals with the cuneiforms

Abnormal spacing

Dorsal or plantar displacement on the lateral view

Malalignment between the second metatarsal and medial cuneiform

Weight-bearing X-rays can be particularly helpful when assessing Lisfranc injuries.

Hallux Valgus: Know Your Angles

When looking at the forefoot, residents should be comfortable identifying the common measurements used for hallux valgus.

These include:

Hallux valgus angle

Intermetatarsal angle

Interphalangeal angle

Distal metatarsal articular angle (DMAA)

Knowing what each angle represents and its normal range can help you understand the severity and pattern of the deformity.

Special X-Ray Views You Should Know

The lecture also covers several specialized views that can be useful in selected cases.

These include:

Saltzman view:
Useful for assessing hindfoot alignment.

Harris axial view:
Can be used in calcaneal fractures and for assessing coalitions.

Broden view:
Useful for evaluating the posterior facet in intra-articular calcaneal fractures and for assessing subtalar fusion.

Canale and Kelly view:
Useful for evaluating the talar neck, particularly intraoperatively in fracture cases.

Stress X-Rays: When Stability Is the Question

Stress radiographs can help assess ligamentous and capsular integrity.

For ankle injuries, gravity stress views can help identify instability by showing widening of the medial clear space.

Stress views may also be used when evaluating lateral ligament insufficiency. In suspected Lisfranc injuries, weight-bearing stress views can help differentiate stable from unstable injuries.

The Take-Home Message for Orthopedic Residents

Foot and ankle X-rays may look simply, but they can provide a huge amount of information if you know what to look for.

The key is not just memorising angles and signs. You need to develop the habit of reading the X-ray systematically — check the views, alignment, spaces, angles, soft tissues and signs, and always correlate the findings with your clinical examination.

That is what makes X-ray interpretation an important skill during residency.

The Conceptual Orthopedics Foot & Ankle X-Ray Interpretation session by Dr. Anuj Chawla is a useful resource for residents who want to strengthen this foundation and become more confident with foot and ankle radiographs.